Break up monolithic iommu table/lock into finer graularity pools and lock
Investigation of multithreaded iperf experiments on an ethernet interface show the iommu->lock as the hottest lock identified by lockstat, with something of the order of 21M contentions out of 27M acquisitions, and an average wait time of 26 us for the lock. This is not efficient. A more scalable design is to follow the ppc model, where the iommu_map_table has multiple pools, each stretching over a segment of the map, and with a separate lock for each pool. This model allows for better parallelization of the iommu map search. This patch adds the iommu range alloc/free function infrastructure. Signed-off-by:Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by:
Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
c12f048f
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